The quake, with a preliminary 3.9 magnitude, and was centered in Berkeley. There were no immediate reports of damages.

The jolt was felt almost 22 years to the day after the Loma Prieta earthquake struck the Bay Area during the 1989 World Series. And it occurred on the same day that more than 8.5 million people signed up to participate in an annual earthquake drill in which people duck under desks and tables.